A quality of service (QoS) control mechanism using bearer as granularity is provided in an evolved packet system (EPS). A service data flow of a user is transmitted between a UE and a service server through a bearer established in the EPS. The EPS provides an available bandwidth for the service data flow by using bearer as granularity, to ensure a guaranteed transmission rate of a service and limit a highest transmission rate of the service.
FIG. 1 is a simplified block diagram of the EPS which a bearer binding is based on in prior art. As shown in FIG. 1, the EPS which the bearer binding is based on includes a policy and charging rules function (PCRF) 11, a packet data network gateway (PGW) 12, a serving gateway (SGW) 13, a mobility management entity (MME) 14, an evolved nodeB (eNodeB) 15 and a user equipment (UE) 16.
A specific implementation of the bearer binding is as follows. The PGW 12 receives a policy and charging control (PCC) rule sent by the PCRF 11, and according to a QoS class identifier (QCI) and an allocation and retention priority (ARP) in the PCC rule, binds a service data flow corresponding to the current PCC rule to an existing bearer with same value as the QoS and the ARP, or establishes a new bearer for the current service data flow corresponding to the PCC rule. When the service data flow corresponding to the current PCC rule is bound to the existing bearer with a same value as the QCI and the ARP, the PGW 12 initiates a bearer modification flow to the SGW 13, namely to modify the existing bearer for bearing the service data flow corresponding to the current PCC rule. The SGW 13 continuously executes a modification program according to a modification message from the PGW 12. The MME 14 receives a modification message sent by the SGW 13 and continuously executes the modification program. The eNodeB 15 receives a modification message sent by the MME 14 and continuously executes the modification program. The UE 16 receives a modification message sent by the eNodeB 15 and continuously executes the modification program. When establishing a new bearer for the service data flow corresponding to the current PCC rule, the PGW 12 initiates a bearer establishment flow to the SGW 13 to establish the new bearer. The SGW 13 continuously executes a bearer establishment according to a bearer establishment message from the PGW 12. The MME 14 receives a bearer establishment message sent by the SGW 13 and continuously executes the bearer establishment. The eNodeB 15 receives a bearer establishment message sent by the MME 14 and continuously executes the bearer establishment, and the UE 16 receives a bearer establishment message sent by the eNodeB 15 and continuously executes the bearer establishment.
However, when two service data flows share a same bearer, a guaranteed bit rate (GBR) of a first service data flow is GBR1, a GBR of a second service data flow is GBR2, and a guaranteed rate of the bearer is GBR1+GBR2, a rate of the first service data flow may continuously exceed GBR1 due to a service characteristic (for example, the first service data flow is a video service), thereby leading that a rate of the second service data flow cannot reach GBR2. As a result, a QoS of the second service data flow cannot be satisfied, thereby decreasing a degree of user experience.